Thanks.
Edit: Unfortunately, it doesn't matter how many ruses I use to try and get in, including using my e-mail address which is how I got in before and which they cite as an alternative to a mobile number, it comes up with the same instruction. Using their "Help Centre" I see there is a method for removing a phone number, but as far as I can tell, this is just to remove it from public view; barefacedbook will still have it. Further, the buttons they suggest using don't appear on my screen!
Typically, there is no "contact us" facility - probably to save money!